feat(k8s): declare 'talos' modules

modules/k8s/default.nix

@@ -1,3 +1,17 @@
+{ config, lib, ... }:
+
 {
-  imports = [ ./crossplane.nix ];
+  imports = [
+    ./crossplane.nix
+    ./talos.nix
+  ];
+
+  options.k8s.enable = lib.mkOption {
+    default = false;
+    type = lib.types.bool;
+  };
+
+  config = lib.mkIf config.k8s.enable {
+    k8s.talos.enable = lib.mkDefault true;
+  };
 }